Motor speed-based anti-pinch control apparatus and method with rough road condition detection and compensation

ABSTRACT

A powered panel control apparatus and method using an electric motor with a rotatable armature. The control generates time periods for a predetermined amount of angular rotation of the motor armature during one complete rotation. An average time period is computed over a predetermined number of time periods and compared with a threshold time period to determine if an obstacle is present in the path of movement of the panel. Transient counts are accumulated for increasing average time periods over a number of time period samples to detect an obstacle. A threshold for normal noise variations is adjusted upon detection of a rough road condition to compensate for the effect of rough road conditions on the powered panel control apparatus.

BACKGROUND

The present invention relates, in general, to control apparatus formotor driven closures which having obstacle detection capabilities, andmore particularly, to motor controls with obstacle detectioncapabilities for moveable closures used in vehicles.

Electric motor drives for windows, sliding roofs and van doors arecommonly employed in motor vehicles to automatically move the closurepanel or door between open and closed positions. However, an automatedclosing system can be dangerous if it cannot accurately detect anobstruction in its path of travel.

Government regulations specify that any automatic closure system must beequipped with an anti-pinch safety feature which meets FMVSS118. Becauseof the safety concerns with these types of obstacle detection systems,sometimes what is intended to be a convenience item on a vehicle becomesan annoyance feature. This is because every obstacle detection designhas to strike a balance between being too sensitive or not beingsensitive enough. If an obstacle detection design is too sensitive,slight variations in the load on the motor can cause the system toerroneously detect an obstacle and reverse the motor rotation therebymoving the closure panel back to the open position. This is oftenreferred to as a “false reversal.” False reversals are an annoyancebecause the automatic closure system did not close when the operator ofthe vehicle initiated a closed command, thus requiring the operator toreinitiate the closed command. If an obstacle detection design is notsensitive enough, then the force on a pinched object, i.e., an arm orhand, etc., may exceed the government regulated force limit of 100Newtons.

There are two basic implementation strategies for anti-pinch obstacledetection systems. The first approach uses sensors that monitor theclosure path. Sensors in the seal around a vehicle window, or aninfrared light curtain are the most common approaches. However, thisapproach is usually very costly to implement.

The second approach is a motor-based system. This type of system detectsobstructions in the closure path by sensing changes in the load on themotor. Most motor-based obstacle detection systems in use today fallinto two categories. One type uses a current shunt to measure thecurrent through the motor. The other approach uses a ring magnet on themotor armature together with a Hall effect sensor to produce a digitalpulse train that corresponds to the period of rotation the armature.These two methods are respectively referred to as current-sensing andspeed-sensing approaches.

However, many of the obstacle detection systems are “history based”meaning that such systems keep track through memory storage of previousdata points, i.e., motor speed, motor current, etc., and compare thecurrent run or motor operation cycle to past data to determine ifchanges have occurred which could be obstacles. However, such “historybased” systems require considerable processing time and therefore areslower in response to a detected obstacle. Such systems also require alarge memory to store the historical data points.

Examples of environmental conditions that may affect or cause variationsin motor speed include the applied voltage, the ambient temperature,joints or weld points in the track of the closure assembly, such as theseal and channel that a side door window travels in, accelerations ofthe assembly in the X, Y or Z axes, etc. For an automotive product,environmental conditions may also include battery voltage when the carengine is off versus alternator voltage when the engine is running. Coldweather, on the other hand, causes the rubber seals around the window tobecome stiff and create more drag on the glass during movement of theglass and when the glass enters the upper seals at the closed position.

If a vehicle hits a pothole or speed bump, the window glass experiencesacceleration in the Z axis. This acceleration of the mass of the windowglass causes a reaction force at the motor armature which, in turn,causes a variation in the speed of the motor.

Any one of these conditions can cause a significant deceleration of themotor armature, thus causing a control algorithm to detect an obstacleand reverse the direction of movement of the window glass when noobstacle is actually present in the closure path of the window.

Existing obstacle detection systems state that they can detect thepresence of rough road. However, it appears that such detection is atthe expense of maintaining a sensitive pinch force level. For example,if a windowlift anti-pinch system has a typical pinch force of 80Newtons, during rough road the allowable pinch force level is raised to150-180 Newtons. While this method does limit the possibility of a falsereversal, it does not maintain an acceptable limit on the pinch force.Further, these pinch forces may not meet government set levels.

Thus, it would be desirable to provide an obstacle detection system fora moveable closure which addresses the deficiencies in previouslydevised obstacle detection systems. It would also be desirable toprovide an obstacle detection system which has a quicker response time,and smaller memory requirements than previously devised obstacledetection systems. It would also be desirable to provide an obstacledetection system which includes compensation for variability in variousoperating conditions so as to accommodate rough road conditions.

SUMMARY

The present invention is a power panel apparatus having a unique, robustobstacle detection control to reverse the direction of movement of thepanel when an obstacle is detected in the path of movement whilepreventing false reversals due to environmental induced faults, such asstartup transient, rough road, end of zone seal entry, voltage andtemperature variations, movement bind positions, and multi-zone time orposition-based step functions.

In one aspect, the inventive powered movable panel control apparatus isused with a panel movable between first and second positions, anelectric motor having an armature for driving the panel between thefirst and second positions, means for detecting deceleration of a motorarmature. The control includes timer means, responsive to the detectingmeans, for generating consecutive time periods between a predeterminedamount of rotation of the armature.

The present invention also defines a method of controlling a power panelincluding the steps of:

determining deceleration of the motor armature;

classifying a degree of relative deceleration with respect to athreshold defining a potential obstacle in the path of movement of apanel driven by the motor;

assigning a weighted value to the relative deceleration of the motorarmature;

accumulating successive weighted values as a total cumulative weightvalue;

comparing the total cumulative weighted value with a total cumulativeweight defining an obstacle in the path of movement of the panel; and

reversing the direction of movement panel when the total cumulativeweighted value equals or exceeds a total cumulative weight defining anobstacle present.

The present power panel apparatus and method provides a robust controlfor detecting an obstacle in the path of movement of a panel whilepreventing false reversals due to any one or more of a number of factorsincluding one or more of startup transient, rough road, end of zone sealentry, voltage and temperature variations, and movement bind positions.

BRIEF DESCRIPTION OF THE DRAWING

The various features, advantages and other uses of the present inventionhave become more apparent by referring to the following detaileddescription and drawings in which:

FIG. 1 is a pictorial representation and block diagram of a vehiclepanel control system having an obstacle detection capability accordingto the present invention;

FIG. 2 is a timing chart used in the present apparatus;

FIG. 3 is a pictorial representation of the noise and object detectionthreshold routine;

FIG. 4 is a graph depicting bind compensation zones;

FIG. 5 is a graph depicting voltage compensation;

FIG. 6 is a flow chart depicting the control process for determiningvoltage compensation;

FIGS. 7A, 7B and 7C are flow diagrams depicting the control process fortemperature compensation;

FIGS. 8A, 8B and 8C are flow diagrams depicting the control sequence forstart-up transient ramp compensation;

FIG. 9 is a graph depicting startup transient compensation;

FIG. 10 is a graph depicting endzone ramp compensation;

FIGS. 11A, 11B and 11C are flow diagrams depicting the control sequencefor endzone ramp, compensation;

FIG. 12 is a graph depicting Tdiff signal variations during rough roadconditions;

FIGS. 13A-13L are flow diagrams depicting the control sequence for roughroad compensation;

FIG. 14 is a graph depicting time based and position based step functioncompensation calculation;

FIG. 15A is a flow diagram depicting the control sequence forcalculation of the time based and position based step functioncompensation;

FIG. 15B is a flow diagram depicting the control sequence for speedbased compensation;

FIGS. 16 and 17 are block diagrams depicting the main sequence steps inthe obstacle detection method according to the present invention;

FIGS. 18A-18E are flow diagrams depicting the individual steps in theobstacle detection method of the present invention; and

FIG. 19 is a pictorial representation of a multi-zone movable controlpanel controllable by the apparatus and method of the present invention.

DETAILED DESCRIPTION

Referring now to the drawing, and to FIG. 1 in particular, there isdepicted an exemplary moveable panel system utilizing an obstacledetection apparatus according to the present invention.

It will be understood that the following obstacle detection controlapparatus according to the present invention, although described inconjunction with a moveable panel or panel, such as a vehicle windowglass, will also apply to any movable panel or partition, such asvehicle sliding doors, pivoting and sliding sunroofs, pivotal vehiclerear lift gates, sliding vehicle running boards, tonneau covers, garagedoor openers, etc.

Thus, as shown in FIG. 1, by example only, a panel 10, such as amoveable window glass in a motor vehicle, is slidably mounted in a pairof opposed channels 12 which form part of a vehicle door frame. Alinkage 14 pictorially represented in FIG. 1 is coupled to the panel 10and is operated by connection to an output shaft of a motor 16,preferably a bidirectional electric motor. The linkage 14 may take anyform, typical of moving panel linkages or drive systems found invehicles.

A power source, such as a vehicle battery, not shown, is connected tothe electrical components of the panel drive system, including the motor16, an open and close switch 18, and a control means or unit 20. Theopen and close switch 18 is typical of a switch found in a motor vehiclefor movement between open and close positions from a center neutralposition. The switch 18 is connected to the vehicle battery or powersource and provides separate output signals, i.e., an open input signalor a closed input signal, upon actuation by a vehicle passenger.

Limit stops 22 and 24, which may constitute hard stops or structuralmembers mounted in the vehicle door, define upper and lower stoppositions, respectively, of the panel 10. The limit stops 22 and 24cause the motor 16 to stall which can be detected by the control means20 to deactivate further operation of the motor 16.

The motor 16 has an armature 28. Means are provided for measuring anddetecting changes in the velocity of rotation of the armature 28. Avariety of different means or sensors can be employed to measure thevelocity of the armature 28. For example, optical encoders or resistivesense means (where a resistance changes with angular position of thearmature) may be employed. With each of these types of velocity sensingmeans, the period of rotation of the armature 28 is divided into atleast one and preferably a plurality of equal angular rotation periodsthrough which the armature 28 rotates a set number of degrees.

Another armature 28 velocity determining means may utilize a ring magnet26 mounted on the armature 28. The ring magnet 26 may be provided withat least one and preferably a plurality of poles depending upon thedegree of resolution desired for the obstacle detection system. Asixteen pole ring magnet 26 will be described hereafter by way ofexample only. It will be understood that ring magnets 26 having othernumbers of poles, such as 2, 4, 8, 32, etc., may also be employed in theobstacle detection system described hereafter.

A detector 30, such as a Hall sensor, is mounted in a position to detectpassage of the poles of the ring magnet 26 therepast. The sensor 30outputs a pulse train 32, shown in FIG. 2, of a generally squarewaveconfiguration having successive rise and fall edges 34 and 36surrounding a high level signal 38 and a low level signal 40. Eachrising and falling edge transition 34 and 36 from low to high or high tolow level signals is output to the control unit 20.

The control unit 20 may be a stand alone control circuit dedicated tothe operation of a panel control system. In one aspect of the invention,the control unit 20 is a central processor based unit operating acontrol program stored in an associated memory. As is typical in motorvehicles, the control unit 20 may be embodied in a motor control unit ora body controller already existing in the vehicle for controlling othervehicle components.

As shown in FIG. 2, the time period between successive edge transitions34, 36, 34, etc., denotes the time period between the passage of eachpole of the ring magnet 26 past the sensor 30. This time period isdirectly related to the speed of rotation of the motor armature 28. Thetime periods between successive edge transitions 34, 36, 34, 36, etc.,are indicated as T1, T2, etc. Any variation in the speed of rotation ofthe motor armature 26 caused by a stall condition when the panel 10reaches one of the limit stops 22 or 24, or if the panel 10 strikes anobstacle in the path of movement of the panel 10 or due to one of theaforementioned external conditions, will cause a change or variation inthe motor armature 28 speed. This speed variation results in acorresponding variation in one of the time periods T1, T2, etc., eitherincreasing or decreasing the time period.

The control unit 20 operates on an interrupt basis to detect each edgetransition 34, 36, etc., calculates the time periods T1, T2, etc., andthen determines an average of the time periods to detect significantvariations in order to determine whether the sensed variation in motorspeed is a result of an external condition or an actual obstacle in thepath of movement of the panel 10.

As described hereafter, the control unit 20 receives the pulse sequenceor pulse train 32 shown in FIG. 2 from the sensor 30. By means of aninternal clock, control unit 20 measures the time period for each edgetransition 34, 36, etc., to generate a precise measurement of the speedof rotation of the motor armature 28.

The control unit 20 records or stores in its associated memory the timeperiod between each transition, T1, T2, T3, . . . T16, etc. For eachsuccessive sixteen time periods, the control unit then calculates anaverage time period TR1. This average period is a measure of speed ofrotation of the motor armature 28 for one complete 360° revolution ofthe motor armature 28. The control unit 20 calculates a new averageperiod TRn for each new transition of the pulse sequence 32 as follows:

TR1 = (T1 + T2 + T3 + T4 + T5 + T6 + T7 + T8 + T9 + T10 + T11 + T12 +T13 + T14 + T15 + T16)/16 TR2 = (T2 + T3 + T4 + T5 + T6 + T7 + T8 + T9 +T10 + T11 + T12 + T13 + T14 + T15 + T16 + T17)/16 TR3 = (T3 + T4 + T5 +T6 + T7 + T8 + T9 + T10 + T11 + T12 + T13 + T14 + T15 + T16 + T17 +T18)/16 ... TR9 =(T9 + T10 + T11 + T12 + T13 + T14 + T15 + T16 + T17 +T18 + T19 + T20 + T21 + T22 + T23 + T24)/16

At a predetermined point in the rotation of the motor armature 28, suchas for every half revolution, quarter revolution, full revolution, etc.,with a half revolution being described hereafter by way of example only,the control unit 20 calculates the relative acceleration of the motorarmature 28 hereafter referred to as TDIFFn. Thus, TDIFF(9)=TR9−TR1.

If an object obstructs the path of movement of the panel 10 moving in aclosing direction between the limit stops 22 and 24, the object willcause the speed of the motor armature 28 to decrease. This decrease inthe speed of the motor armature 28 will cause the time between edgetransitions 34, 36, etc., in the pulse sequence 32 to become longer,thus increasing the average period TRn. When TRn becomes larger, thenTR(n)−TR (n−8) becomes larger. Thus, it is clear that an objectobstructing the path of movement of the panel 10 when moving in aclosing direction will cause TDIFF(n) to become a large positive number.

The panel anti-pinch function has to determine whether or not anobstacle is present. This is determined by two failure modes:

1. force loads on the objector obstruction exceed 100 N with an obstaclepresent, and

2. detection of an obstacle without an obstacle being present.

In order to avoid the second failure mode, the control system must takeinto account all disruptions in the system during a thresholdcalculation phase to calculate a total offset or acceptable noise level.All current TDIFF values are compared with the total offset to evaluatewhether or not an obstacle is present and by indicating the probabilityof an obstacle being present. A post threshold calculation phaseconsists of making a final decision whether or not an obstacle ispresent.

First, the anti-pinch function utilizes a default value. Additionalcompensations or offsets are provided as a voltage offset, a temperatureoffset, a bind offset, startup transient ramp, end of zone ramp, roughroad, or time based step offset and position based step offset. Theseoffsets and all compensations are totaled to generate a total offsetnumber 50. The total offset 50 divided by four equals a “bandwidth”.

As shown in FIG. 3, the total offset 50 establishes level one. Aplurality of spaced levels, each separated by one bandwidth ascalculated above are then established as levels two through level six,for example, only. Each level corresponds to a different stiffness levelsuch as a threshold stiffness at level two, a soft object stiffness atlevel three, a medium object stiffness at level four, a hard objectdetection stiffness at level five and a hardest object detectionstiffness at level six. A transient counter 52 is employed in theprocessor. Transient counts of varying magnitude, such as transientcounts 54, 56, 58, 60 and 62 are provided for TDIFF values fallingbetween any two levels. For example, a minimum threshold is establishedas level two. If T diff is between levels two and three, the transientcounter 52 is incremented by a transient count 54 of one. If TDIFF has amagnitude between level three and four, the transient counter 52 isincremented by a transient count 56 equal to two. A TDIFF magnitudebetween levels four and five is assigned a transient count 58 of four. ATDIFF value between levels five and six is assigned a transient count60. Finally, a TDIFF value greater than level six is assigned atransient count 62 of eleven. The transient counter 52 is anaccumulative counter for each new transient count generated with anyTDIFF signal.

However, certain rules are applied to the transient counter 52 whichcontrol its function or output. If a T diff value below level one 50 ismeasured for three consecutive TDIFF signals, the transient counter 52is reset to zero. If the transient count is different from zero betweentwo consecutive TDIFF signals, then the transient count associated withthe magnitude of the TDIFF signal with reference to levels two throughsix is added to the count accumulated in the transient counter 52. Whenthe count value of the transient counter 52 exceeds an overflow number66 equal to a transient count of twelve, for example, the control orprocessor 20 provides an output signal indicative of an obstacle presentor detected, which signal defines a panel reverse movement signal.

The TDIFF signals are rounded off so as to be quantified as an absolutevalue. The bandwidth between successive levels in terms of TDIFF signalmagnitude is determined by the equation:

level_(x+1=)level_(x+)level_(x/4).

The bandwidth, which is rounded off as an absolute values, maybeconstant between each level 1-6 or may vary, such as in increasingbandwidth magnitudes as the level number increases indicating a greaterstiffness object being potentially detected in the path of movement ofthe panel.

In the threshold calculation stage, the offset level 50 and thetransient level 64 is calculated by using the compensations as describedabove. These compensations include bind, voltage, temperature, startuptransient, endzone ramp and rough road compensations. These will bediscussed in the listed order given.

Mechanical Bind

As shown in FIG. 4, bind compensation zones exist in at least in one andusually in a plurality of angular positions due to wearing down of themotor drive gear teeth. The binds cause a periodic disturbance orincrease in TDIFF as might be noted regularly during panel travel.Typically, there may be up to four or five disturbances in T diff duringthe complete panel travel between first and second or open and closedpositions. To compensate for these bind zones, the control 20 needs toknow the ratio of the motor gear in order to calculate the position ofthe appropriate zones knowing the full closed or second position of thepanel. The bind compensation or offset threshold can be calculatedempirically.

Voltage Compensation

Voltage level has an influence on motor speed and must be compensated atvoltages other than a nominal voltage, such as sixteen volts at roomtemperature.

The following chart shows changes in TDIFF values for different systemvoltage levels.

TDIFF Voltage compensation Temperature Voltage value (TDIFF Vcomp) 20C(Room temp) 16 V 15 0 20C (Room temp) 13 V 26 (26-15) = 11 20C (Roomtemp) 10 V 35 (35-15) = 20 20C (Room temp) ... ... ...

TDIFF_(Vcomp)=F(Voltage) is an exponential function and may berepresented by:

X _(K) =X _(k−1)+(X _(k−1)/4+X _(k−1)/8)

This equation may be solved at any system voltage level. For example, asshown in FIG. 5, a system voltage of thirteen point four V can becalculated. A measured TDIFF value is established for each differentvoltage and assigned a voltage compensation value as shown in the lookuptable in FIG. 6, which depicts the program steps for determining thevoltage compensation value.

Temperature Compensation

Ambient temperature also affects the movement of the motor armature. Fora particular voltage level, such as thirteen volts, different TDIFFvalues are evaluated and assigned a temperature compensation value, fromthe lookup table in FIG. 7B, by example.

FIGS. 7A-7C depict the program or control steps executed by thecontroller 20 in determining a temperature compensation value.

Startup Transient

There exists a startup transient on the response of the motor armaturespeed during the initial stages of a panel movement. This startuptransient can last anywhere between seventy milliseconds to threehundred fifty milliseconds over which the panel may move severalmillimeters.

When power is applied to the motor, the armature speed signal has atransient component and a steady-state component. Most prior artanti-pinch systems do not enable the anti-pinch feature until thetransient response dies out. During this time, the panel is closingwithout obstacle detection enabled. Since the panel may move severalmillimeters during this time period, a problem can exist if there is anobject directly in the panel path of the panel when the motor isinitially powered on. Laboratory tests have shown that most systemsexert over two hundred N of force on an object when moved toward theclosed position in this manner.

A startup transient control sequence according to the present inventionhas a first step of establishing a first and second boundary for themagnitude of the TDIFF signal at startup. The first boundary isestablished at zero. The second boundary is calculated based on ameasure of the applied voltage and the ambient temperature by thefollowing equation:

A*VOLTOS+b*TEMNPOS+1=Upper Boundary

In the present example, a=0.5 and b=0.5.

With these boundaries established, the control 20, as shown in FIGS.8A-8C, then measures the difference between each new TDIFF sample. Thecontrol 20 only stores the largest recorded value of:

TDIFF(n)−TDIFF(n−1)=JERK(n)

and

TDIFF(n−1)−TDIFF(n−2)=JERK(n−1)

Where

IF JERK(n)>JERK(n−1)

Output JERK(n)=>MAXJERK

Else

Output JERK (n−1)=>MAXJERK

Once TDIFF is greater than the second boundary, the largest recordeddifference for TDIFF between the second and first boundaries, MAXJERK,is compared to JERK(n) when TDIFF>Second Boundary. However, now thelesser value of JERK(n) is recorded.

FOR TDIFF>Second Boundary:

TDIFF(n)−TDIFF(n−1)=JERK(n)

Where

IF JERK(n)<MAXJERK

Output JERK(n)=>MAXJERK

Else

Output MAXJERK=>MAXJERK

Once this differentiation takes place, the resultant MAXJERK is added oraccumulated in a RAMPOS variable:

RAMPOS(n)=RAMPOS(n−1)+MAXJERK(n)

In order to keep this compensation function bounded, a saturation limitis calculated based on the applied voltage and ambient temperature. Thissaturation limit represents the maximum expected overshoot of the TDIFFsignal. A general equation for calculating the maximum expectedovershoot is given as:

a*VOLTOS+b*TEMPOS+C=Saturation Limit.

The present aspect uses a=1.5, b=0, c=7.

Where

IF RAMPOS(n)>Saturation Limit

Output Saturation Limit=>RAMPOS(n)

Else

Output RAMPOS(n)=>RAMPOS(n)

This process continues until the value of JERK(n)<0 AND JERK (n−1)=<0.

Once the TDIFF signal peaks and begins to decay, the control 20 startssaving the largest difference between TDIFF samples and subtracts thisvalue from the compensation function RAMPOS until RAMPOS reaches zero.

RAMPOS(n)=RAMPOS(n−1)−MAXJERK(n)

FIG. 9 shows a sample of the TDIFF signal with the horizontal time axispartitioned into different zones showing how the TDIFF signal isanalyzed and manipulated.

In Zone one, the transient compensation control waits until the inputbuffers are filled with valid data. In Zone two, the variables and flagsused in the compensation algorithm are initialized. In Zone three, thecontrol records the largest differential between TDIFF samples. In Zonefour, the control records the smallest differential between TDIFFsamples, and adds/accumulates this value to create a compensationfunction for the startup transient. The accumulated value is neverallowed to grow beyond a Saturation Limit. In Zone five, the controlrecords the largest differential between TDIFF samples, and subtractsthis value from the compensation variable RAMPOS. Zone five ends wheneither the value of the RAMPOS variable reaches zero, or a limit timerruns out, or TDIFF<0. This limit timer correlates to the expectedsetting time of the mechanical panel system. When the limit timer timesout, it is expected that the transient response of the system has diedout, and compensation is no longer required.

Endzone Ramp

When the controller 20 is powered on, it is in a calibration statebecause, when it lost power, it had no way to save position information.When the controller 20 receives a switch 18 input command to power themotor 16 in the closed direction (all the functionality of which is hardcoded in the FLASH program memory), it records a count of the number ofhall pulses until a stall condition occurs (when the panel is fullyclosed into the upper seals). A stall condition is when the motorarmature 28 turns less than 22.5 degrees in one hundred thirty-onemilliseconds. The controller 20 looks for several events while the panelis closing. The controller 20 records the TDIFF signal when the panelfirst contacts the seal. Then, when the controller 20 receives a switch18 input command to power the motor 16 in the open direction, it recordsthe total number of counts from full closed to full open. Once thisoccurs, the controller 20 is calibrated, and it knows where the sealbegins, and where to turn off anti-pinch. The controller 20 does this bylooking for a few key events when the panel is closing into the seals asshown in FIG. 10. When the controller 20 is powered on, it resets theposition count to a default constant.

The endzone ramp calibration will now be described. The end of zone rampfunction starts incrementing a variable when the panel 10 reaches apredetermined position between the first and second positions. Thevariable is incremented at a set rate based on a predetermined slope.The position at which the ramp is enabled and the slope of the ramp aredetermined at system calibration. The end of zone ramp compensationfunction is designed to keep anti-pinch enabled until the opening isless than a prescribed small amount, such as much less than 4 mm.

The control program steps for implementing the end zone ramp calibrationare shown in FIGS. 11A-11C. First, the controller 20 requires that themotor 16 has been running long enough that the transient response atstartup has died out. Second, the panel 10 has to have traveled at leasttwo inches before encountering the upper seals. If these two conditionshave been met, then the controller 20 begins to monitor the TDIFF signalfor certain behavior. First, the controller 20 records the value of theposition count the first time TDIFF is greater than a threshold level,generally around 8-15 counts. (this is called the beginning of theEndzone Ramp) Next the controller 20 records the position count thefirst time TDIFF is greater than 50 counts. (This is called the endingposition for the Endzone Ramp.) If, after either of these events, thevalue of TDIFF drops below the first threshold, the recorded values ofthe position count are not over-written. The recorded values of theposition count are only over written when TDIFF becomes greater than thelower threshold is more than a set number of counts from the positioncount that was recorded the first time TDIFF became greater than thelower threshold. Once the controller 20 registers a stall event, thecontroller 20 compares the final position count to the position countrecorded when TDIFF crossed the lower threshold. If the difference isless than a certain amount, then the recorded positions are assumed tobe valid. The controller 20 then calculates the slope of TDIFF betweenthe two thresholds. The result of this rise over run calculation isstored in memory, as well as the position counts of where TDIFF crossedthe lower and upper boundaries. Then, when the panel or window is rundown (or the sunroof is opened), the position count when stall occurs isloaded as the true default open position, and the position countsrecorded in memory for the beginning of the Endzone Ramp and the end ofthe Endzone Ramp are shifted by a set index. At this point, the systemis calibrated.

When the system is run closed with anti-pinch enabled, an Endzone Rampcompensation is included in the TOTALOS when the position count crossesthe position recorded in memory as the beginning of the Endzone Ramp.This compensation variable is increased as a function of the slopebetween the beginning of the Endzone Ramp and the end of the EndzoneRamp. Anti-pinch is enabled until the position count is greater than theposition count recorded in memory as the end of the Endzone Ramp. Thismeans that obstacle detection is enabled until the panel is well withinthe seals. In order for the system to maintain calibration over the lifeof the product, this algorithm can be rerun during the life of theproduct. This means any drift of the seal position relative to the motorrotation can be eliminated. Anytime a full-closed position is recordedthat is greater than the full-closed position recorded when the systemwas calibrated, then the beginning and ending of the Endzone Rampfunction is shifted by this differential. This assumes that the totaltravel distance will only increase over the life of the product, whichhas been shown to be true in laboratory tests. The algorithm describedherein allows for a controller 20 to be placed on any panel andregardless of the tolerance stack-ups of that particularmotor-regulator-panel-frame assembly, the controller 20 will be able tocalibrate itself so that the zone where anti-pinch is active will alwaysdetect at least a 4 mm object. Also, slight weighted offsets can beintroduced when calculating the slope and the locations of the beginningand ending of the Endzone Ramp. These weighted offsets allow a rampfunction to compensate for seal/panel designs where the entire edge ofthe panel does not engage the seal all at the same time.

Rough Road Compensation

The controller 20 looks for a rough road condition by analyzing thebehavior of the TDIFF signal, and mapping how the TDIFF signal changeswith respect to time and sample count as shown in FIG. 12. Rough roadconditions cause an oscillation and an acceleration of the panel orwindow glass. This acceleration of the panel mass produces a reactionforce at the motor 16. The acceleration of the motor 16 oscillatespositive and negative at the passband frequency of the vehiclesuspension and the panel lift regulator. This oscillation can becharacterized and cancelled out by mapping the expected response of themotor acceleration on rough road and then by constantly analyzing theacceleration of the armature to determine if the current motoracceleration has the same profile. This is a pattern recognitionalgorithm.

There are several distinct steps for rough road compensation as shown inFIGS. 13A-13L. First, an analysis of the TDIFF signal is done in orderto generate six input flags for the state machine. The inputs are passedto a state machine set up by the controller 20. Next the output flags ofthe state machine are acted on. If necessary, a frequency timer isupdated that measures the fundamental period of the TDIFF signal. Then acheck is made if this fundamental frequency is within a valid range (thepassband of the suspension and panel lift regulator). If it is, and ifthere has been a valid progression through the state machine, then anoffset is calculated to be passed to the Interrupt Service Routinedescribed later.

Specifically an average for TDIFF is calculated,

(TDIFF(n)+TDIFF(n−1)+TDIFF(n−2)+TDIFF(n−3))*0.25=RDIFF(n)

Then the slope of the average RDIFF signal is determined.

RDIFF(n)−RDIFF(n−1)

The result of this calculation is used to set one of three flags:

FLAG0: slope of RDIFF signal is negative

FLAG1: slope of RDIFF signal is zero

FLAG2: slope of RDIFF signal is positive

Next, the magnitude of TDIFF(n) is classified in one of threecategories:

FLAG3: TDIFF(n)<−(KDNOISE+OSLIMIT(n))

FLAG4: −(KDNOISE+OSLIMIT(n))<TDIFF(n), (KDNOISE+OSLIMIT(n))

FLAG5: TDIFF(n)>(KDNOISE+OSLIMIT(n))

Where KDNOISE is a measure of the minimum noise possible in a system,typically 2-10 and OSLIMIT(n) is a measure of the noise variation as afunction of VOLTAGE, typically an exponential function of voltage.

Then these six input flag bits are passed to the state machine. Thestate machine checks the current state as indicated by the six inputflags. Based on the previous state, the state machine maps to a statewith the correct output flags.

The state machine has two standard output flags:

FLAG6: 0=disable rough road timer

1=enable rough road timer

FLAG7: 0=disable rough road offset

1=enable rough road offset

The state machine has nine basic states, one error state, and onemeta-state. The basis states are labeled A through I. Using the FLAGxdesignations above, the basic states A through I are:

INPUT STATE OUTPUT 010 010 STATE A 00 010 001 STATE B 00 001 001 STATE C00 001 010 STATE D 01 001 100 STATE E 01 010 100 STATE F 01 100 100STATE G 11 100 010 STATE H 11 100 001 STATE I 11

The meta state and the error state are mapped to based on the currentinput flags and the previous state.

The Error State is a special case that resets the output flags when thetransition from one state to another does not represent a logicalprogression expected for rough road conditions. The Error State has theform:

INPUT: STATE X: OUTPUT: XXX XXX ERROR STATE 00

For example, if the TDIFF signal maps from a STATE A, STATE B, or STATEF to a STATE G, and at not time during the previous 25 samples did theTDIFF signal map to a STATE C, STATE D or STATE E, then the statemachine maps to the error state, and stays in the error state until theTDIFF signal has been stable in STATE A for 20 samples.

The meta-state is an unstable STATE A. A counter is used to track howmany consecutive times a STATE A occurs. If the meta-state exceeds a setlimit, then the output flags FLAG6 and FLAG7 are reset. As long as themeta-state counter is below the set limit, the output flag will beunchanged. So if a STATE F precedes a STATE A, the output flags will be01, as long as the value of the meta-state counter is below the setlimit.

A secondary function is incorporated with the primary state machine tokeep a better record of past behavior with minimum memory requirements.The secondary function consists of two flags and a counter. The firstflag is a TROUGH FLAG. This flag is set when the state machine settlesin a STATE C, D, or E. The second flag is a PEAK FLAG. This flag is setwhen the state machine settles in a STATE G, H or I, and the TROUGH FLAGwas already set. When one flag is set, the other flag is cleared. Whenthe state machine settles into a STATE A, B or F, for a set number ofsamples (50 samples on the H-car, 15 on the CK truck), then both thePEAK FLAG and the TROUGH FLAG are cleared. This implies that a givensystem should transition between troughs and peaks within a set numberof samples in order to be classified as a rough road signal. The counteris a transitional event counter, called TECOUNT. The PEAK FLAG is onlyset when the TDIFF signal has transitioned from a TROUGH condition to aPEAK condition within a max set of samples. If the PEAK FLAG is set, andthe rough road frequency timer is within a valid range, then acompensation value is calculated and stored in the ROUGH ROAD OFFSET.

The interaction between the state machine, the TROUGH and PEAK flags,and the TECOUNT is described by the following table:

TE- STATE x COUNT PEAK TROUGH TECOUNT+ PEAK+ TROUGH+ STATE A <32 h X XTECOUNT + 1 X X STATE A >32 h X X 0 0 0 STATE B <32 h X X TECOUNT + 1 XX STATE B >32 h X X 0 0 0 STATE C X X X 0 0 1 STATE D X X X 0 0 1 STATEE X X X 0 0 1 STATE F <32 h X X TECOUNT + 1 X X STATE F >32 h X X 0 0 0STATE G X 0 0 0 0 0 STATE G X 0 1 0 1 0 STATE G X 1 0 0 1 0 STATE H X 00 0 0 0 STATE H X 0 1 0 1 0 STATE H X 1 0 0 1 0 STATE I X 0 0 0 0 0STATE I X 0 1 0 1 0 STATE I X 1 0 0 1 0 ERROR <32 h X X TECOUNT + 1 X XERROR >32 h X X 0 0 0

The secondary function implies that a Peak event should always bepreceded by a Trough event, and additionally, a Trough event shouldalways transition into a Peak event within a limited number of samples.

After the state machine has transitioned to the next state, the roughtimer is tested to see if it is a valid range. For the ideal case, theelapsed time from STATE D to STATE H should be one-half the fundamentalfrequency (where T=1/f) of the vehicle suspension.

The state machine has two main output flags. The first main output flagenables a rough road timer. This timer is used to measure the period ofthe acceleration signal. The fundamental frequency of the TDIFF signalmust be near the passband frequency of the suspension (around 12 Hz inmost automobiles) in order to meet one condition for enabling rough roadcompensation. The second output flag is the ENABLE OFFSET flag. Therough road compensation function should only calculate an offset whenthe state machine's current state is G, H or I.

A rough road offset is calculated:

IF:

the rough road timer is within a valid range

AND

the ENABLE OFFSET flag is set

AND

the PEAK flag is set

AND

the Startup Transient response is extinct.

If all of these conditions are True, then the final step is to calculateas offset. The offset equation has the form:

TDIFF(n)*⅝=IRROS with a saturation value defined asWn*(TRES(n−128)*{fraction (1/9)}+OSLIMIT/2)

Where Wn represents a damping coefficient proportional to the stiffnessof the vehicle suspension. For example, a pickup truck might use adamping coefficient of 1.5, but a luxury car may only need a dampingcoefficient of 0.5. A saturation limit sets a realistic upper bound onthe magnitude of rough road disturbance to be compensated. In practicalterms, an acceleration greater than 1.5 g should be considered extreme.

Step Offset

The step function is used to compensate for expected large variations inthe TDIFF signal. Although there are two different types of stepfunctions, both are classified under the same offset variable in thecontrol program.

The first step function is based on time and is shown on the left sideof the graph depicted in FIG. 14. During system characterization, somesystems demonstrate quite an under-damped response at startup. Thisphenomenon shows up as a decaying oscillation in the TDIFF signal.Mathematically, it would have the form of: αχCos(bt)χl−AT. However,different systems have varying responses.

Some systems, such as that depicted on the left side of the graph inFIG. 14 show quite a bit if “ringing” at startup. The under-damped stepis enabled as a function of time and the magnitude is set as a functionof voltage. The control sequence executes the following steps:

1. The TDIFF data is reviewed and the value of the second positive peakis recorded. The time from start to the third, fourth, or fifth “hump”,is recorded where it can be said that the transient response is extinct.

2. These values are built into a lookup table.

A function is generated based on the magnitude of the second positivepeak as a function of voltage having the form:

αχIVOLTUS+b. This is the equation used to calculate the value of theunder-damped step response.

The duration of the transient can either be made a constant (only ifnecessary for size restrictions) or as an equation having the formαχIVOLTUS+b, where “b” is the minimum decay time for the transientresponse, and, “a” is the modifying term of the voltage offset thatequals the maximum decay time for the transient response. All times aremeasured in terms of MODECT, which has a resolution of 4 ms. By way ofexample:

IF

mindelay time=90 ms

THEN

MODECT value is 90/4=22.

IF

maxdecay time=120 ms

THEN

MODECT value is 120/4=30

The second type of step function accounts for seal irregularities at theend of travel. There are several panel systems, such as vehicle doorsystem designs, where one edge of the glass makes contact with the sealwhile there is a significant (+6 mm) opening between another edge of theglass and the seal. The second position step function takes into accountthe disturbance in the TDIFF signal while allowing anti-pinch to remainactive.

The second endzone step function is enabled as a function of position,as shown on the end of the graph of FIG. 14. If it is observed that thepeak positive value for TDIFF noise increases notably near the upper endof panel travel, then a step function may be necessary. For example, ifit seems that in the last ⅕th of travel, the TDIFF signal noise doublesin magnitude regardless of voltage, then the following procedure isinstituted:

1. Record the position count where TDIFF is increasing,

2. Record the peak magnitude of TDIFF in this last region of travel,

3. Build a lookup table of these values over voltage and temperatureand, 4. Create a function based on temperature and voltage that mapsthis increase in TDIFF.

This function becomes the equation to be implemented for the magnitudeof ISTEPOS based on position.

Speed (RPM) Compensation

Speed compensation is designed to replace voltage compensation duringsteady-state operation of the motor 16. Since panel velocity is a directmeasurement of the kinetic energy in a system, the speed of the motor 10can be used to determine the expected variation in TDIFF. Speedcompensation improves the robustness of the system by allowing forgreater variation in the performance of the motor 10 relative to theapplied voltage.

As some independent factors, such as in incorrectly coupled or mountedmotor in a system or a harness resistance which may be significantlydifferent from the value used for characterization, or the regulatorhaving a wide tolerance for efficiency, may interfere with speedcompensation. Monitoring the speed of rotation of the armature 28instead of monitoring voltage can address all of these factors. Theslower the speed of rotation of the armature 28, the lower the inertiaof the system, and the greater the sensitivity of the TDIFF signal.

The control sequence used to implement speed compensation is shown inFIG. 15. A value proportional to the speed of rotation of the armature28 is used as an address to a speed lookup table which outputs acompensation value for the noise level 50.

Referring now to the block diagrams in FIGS. 16 and 17, and to the flowcharts in FIGS. 18A-18E, there is depicted the main functional steps inthe control program and interrupt service routine employed by thecontrol 20 of the present invention.

The main or top level control sequence 200 is shown in FIG. 16. Oncereset and sequence to a wake-up program, the control checks variousstatus flags in step 202 and then initializes inputs and outputs andperipherals in step 204. Step 204 generally includes checking statusflags, initializing the random access memory, initializing ports bysetting inputs and outputs and turning on the motor armature 28, theHall sensor 30, initializing peripherals including timers and timerprescalers, initializing panel position, initializing interrupts, andenabling interrupts then entering the main routine in step 206. In themain routine, the control executes step 208 which causes a polling ofvarious functions, including software timers, speed control, stall timercheck, soft stall check, position error checking, anti-pinch enable andendzone calibration.

From the polling step 208, anti-pinch compensation routines are nextpolled in step 210. This step includes setting the variouscompensations, such as one or more of temperature, voltage, bind, roughroad, endzone ramp and startup transient ramp.

Next, in step 212, the control 20 polls the various switch inputs, readsbattery voltage, reads and calculates ambient temperature and registersvalid switch state changes.

Next, in step 214, the control 20 executes a switch decode and modeselect function by reading the debounce switch initializing mode timers,reading the mode timers and then setting the mode to one of auto-up,auto-down, manual-up, manual-down or halt. The control 20 then sets themotor 16 state flags.

During the main routine, step 216 is executed in response to switchchanges or the detection of an obstacle. The control 20 reads the motor16 state flags, turns the motor 16 on, loads the PWM duty cycle,initializes the stall timer, turns the motor 16 off when at the closedor second position or an object is detected and then resets andreinitializes the anti-pinch algorithm variables. The control 20 alsoexecutes step 218 to handle stall events when appropriate. In executingthis function, the control 20 sets the motor 16 state flags for off,disables the stall timer, adjusts and updates the panel position zones,adjusts and updates panel position, records calibration event data andchecks panel limits.

Finally, step 220 enters a sleep-low power standby mode. In executingstep 220, the control 20 turns the motor 16 off, turns off the Hallsensor 30, disables the interrupts, polls the ignition line, polls thedebounce ignition line, sets the power status bits and goes to a resetvector/wake-up from sleep standby mode.

FIG. 17, depicts an interrupt service routine 230. In step 232, thecontrol 20 executes an initial capture event at the rising and fallingedge of the output signal from the Hall sensor 30. The control 20 resetsand reinitializes the edge detection interrupt flags, toggles the edgeselection, polls the direction input line and updates position countinformation.

Next, in step 234, the control 20 reads and generates an average newtimer sample. The control 20 executes this function by resetting thestall timer, storing a new timer sample, calculating a new average,storing the new average, calculating a new TDIFF and then storing thenew TDIFF sample in memory.

Next, in step 236, the control 20 sets noise thresholds by loading adefault noise threshold, adjusting the default with offsets passed fromcompensation routines in the main flow sequence, calculates thethreshold bandwidth, calculates the stiffness thresholds and then checksthe overall range of the compensated thresholds.

Finally, in step 238, the control 20 looks for an obstacle. In executingthis function, the control 20 compares TDIFF to noise and stiffnessthresholds, see FIGS. 18C-18E, updates the transient reset debouncecounter, resets the transient count, updates the transient count, haltsthe motor 16 upon detection of an obstacle as described above,calculates the minimum reversal point and then sets flags to run thepanel in an opposite direction to an open or down position.

Multi-Zone Compensation

The present invention also contemplates an obstacle detection systemhaving a plurality of different zones of operation wherein a panel, suchas a vehicle sun roof, sliding window, sliding door, etc., has twodifferent modes of movement on operation between two positions can bedivided into multiple zones due to different operating parameters orenvironmental conditions in each zone, such as when a sliding glasspanel pivots due to a lever arm in the mechanism in one zone versussliding in a channel in the mechanism in another zone.

In FIG. 19, a pivotal, sliding vehicle sunroof panel 300 is depicted.The panel 300 is typically mounted in a normal first position closing anopening in a vehicle roof, not shown. Also not shown, are the drivemotor, actuator, and linkage which interact to slide the panel 300 fromthe first position in the direction of arrow 302 to a second positiondenoted by reference number 304 wherein the panel 300 at least partiallyopens the roof opening, and a second pivoted position shown in thedirection of arrow 306 to a raised, pivoted position 308.

As the speed variations are different when the panel 300 moves in thedirection of arrow 302 from the direction of movement 306, the presentinvention contemplates an obstacle detection, anti-pinch control whichhas different threshold levels for obstacle detection, one for each modeor zone depicted by movement arrows 302 and 306.

For example, the noise or offset 50 level magnitude in FIG. 3 can bevaried for each of the modes or zones 302 and 306 to effect differentdetection levels which are used to determine the presence of an obstaclein the path of movement of the panel in the direction of arrows 302 or306.

Similarly, the time based and/or position based step functions describedabove and shown in FIG. 14 also can be used to create a multi-zoneapproach to obstacle detection for a movable panel. The offset level 50for the time based step function or the position based step functiondepicted in FIG. 14 can be different and merely selected from a lookuptable depending upon the mode of operation of the system.

Further, any one or all of the compensation factors, such as rough road,voltage, temperature, etc., can have different look up table values orutilize different algorithm in each zone.

In summary, there has been disclosed a unique motor speed basedanti-pinch control apparatus and method having a robust control whichaccommodates multiple modes of movement of the panel, includescompensations for various events, including buying condition, voltage,ambient temperature, rough road, end of zone ramp, startup transient,time or position based offset.

What is claimed is:
 1. A powered movable panel control apparatus for apanel movable between first and second positions by an electric motorhaving an armature comprising: means for detecting deceleration of themotor armature; timer means, responsive to the deceleration detectingmeans, for generating consecutive time periods for rotation of thearmature over a predetermined angular extent during at least a portionof one complete revolution of the armature; means, responsive to thetimer means, for calculating an average time period over thepredetermined number of time periods; means, responsive to the averagetime period, for calculating the deceleration of the motor armaturebetween two time spaced points on the armature rotation; means forcomparing the deceleration with a threshold defining normal motordecelerations resulting from motor armature load variations; meansresponsive to a comparison exceeding armature load threshold forclassifying the deceleration as a relative deceleration with respect tothe threshold; means for assigning a weighted value based on therelative deceleration with respect to the threshold; means foraccumulating successive weighted values as a total cumulative weightedvalue; means for comparing the total cumulative value to a definedobstacle detection weighted value; means, responsive to the comparingmeans, for generating a panel reverse direction signal when the totalcumulative weighted value exceeds the defined obstacle detectionweighted value; means for detecting rough road conditions; and means,responsive to the rough road condition detection means, for adjustingthe threshold when rough road conditions are detected.
 2. The apparatusof claim 1 wherein the means for calculating the average time periodincludes: means for calculating the average time period over apredetermined constant number of successive time periods.
 3. The systemof claim 1 wherein: the average time period is calculated for thepassage eight poles past the sensor.
 4. The apparatus of claim 3wherein: the average time period is calculated for eight successivepoles of a total of sixteen successive poles passing the sensor.
 5. Theapparatus of claim 1 wherein the means for detecting rough roadconditions comprises: means for monitoring the average time period withrespect to a maximum and minimum limit.
 6. The apparatus of claim 5further comprising the step of: monitoring the change in slope of a timesequential average time period signal.
 7. The apparatus of claim 1wherein the means for detecting deceleration comprises: magnet means,coupled to the armature, the magnet means having a plurality of poles; asensor detecting passage of each of the plurality of poles of the magnetmeans therepast, and generating an output signal for each pole passage.8. The apparatus of claim 1 wherein the means for detecting rough roadconditions comprises: means for monitoring the magnitude of the averagetime period to detect a peak magnitude above a threshold followed by adecrease in the average time period magnitude.
 9. The apparatus of claim8 further comprising: timer means for establishing a preset time windowfor a peak magnitude following a decrease for detecting rough roadconditions.
 10. A method for controlling panel movement by an electricmotor controlled by a control, the method comprising the steps of:detecting deceleration of an electric motor armature; calculating anaverage time period over a predetermined number of time periods;determining the deceleration of the motor between two selected timeperiods based on changes in the average time period; comparing thedeceleration with a threshold defining an obstacle in the path ofmovement of the panel; upon detecting a deceleration greater than orequal to the threshold, generating a panel reverse direction signal toreverse the direction of movement of the panel; detecting a rough roadcondition; and upon detecting a rough road condition, adjusting thethreshold.
 11. The method of claim 10 further comprising: providing athreshold transient count.
 12. The method of claim 11 further comprisingthe step of: adjusting the threshold transient count upon detectingrough road conditions.
 13. The method of claim 10 wherein the step ofdetecting the deceleration of the motor armature comprises the step of:determining successive time periods between the passage of at least onepole of a plurality of poles of a rotating motor armature past a sensor,the sensor generating an output on each detected pole passage.
 14. Themethod of claim 10 wherein the step of detecting a rough road conditioncomprises the step of: monitoring the magnitude of the average timeperiod to detect a peak magnitude above a threshold following a decreasein the average time period magnitude.